Says who? Theres more to graffiti than just bombing... I don't see anything wrong with it. In my eyes there is no difference between obey selling some shit and writers being featured in graffiti magazines, documentaries, etc. the magazines get sold, the dvds get sold, people get paid.
just cause you broke and don't have no business plans doesn't mean you gotta hate on those that do
edit:
Hell, even 12oz has advertising!